Analysis of association between butyrylcholinesterase K variant and apolipoprotein E genotypes in Alzheimer's disease

Confirmed Synergy Between the ɛ4 Allele of Apolipoprotein E and the Variant K of Butyrylcholinesterase as a Risk Factor for Alzheimer's Disease: A Systematic Review and Meta-Analysis

Background

Alzheimer's disease (AD) has several risk factors. APOE4 is the main one, and it has been suggested that there may be a synergy between it and BCHE-K as a risk factor.

Objective

To investigate the association between APOE4 and BCHE-K as a risk factor for AD.

Methods

We searched PubMed, Web of Science, Embase, and Scopus on August 8, 2021 for studies that analyzed the association of APOE4 and BCHE-K with AD. The random effect model was performed in meta-analysis according to age group. A chi-square was performed with the meta-analysis data to verify if the effect found is not associated only with the E4 allele.

Results

Twenty-one studies with 6,853 subjects (3,528 AD and 3,325 Controls) were included in the meta-analysis. The quality of the evidence is moderate. There is a positive E4-K association for subjects with AD as shown by the odds ratio of 3.43. The chi-square meta test, which measures the probability that the E4-K association is due to chance, has an odds ratio of 6.155, indicating that the E4-K association is not a random event. The odds ratio of an E4-K association in subjects with AD increases to OR 4.46 for the 65- to 75-year-old group and OR 4.15 for subjects older than 75 years. The probability that the E4-K association is due to chance is ruled out by chi-square meta test values of OR 8.638 and OR 9.558.

Conclusion

The synergy between APOE4 and BCHE-K is a risk factor for late-onset AD.

Association of Matrix Metalloproteinase-2 (MMP-2) and MMP-9 Promoter Polymorphisms, Their Serum Levels, and Activities with Coronary Artery Calcification (CAC) in an Iranian Population

The serum levels and activity of matrix metalloproteinases (MMPs) are associated with the risk of coronary artery calcification (CAC). We sought to investigate the association between MMP-2 -1575G>A (rs243866) and MMP-9 -1562 C>T (rs3918242) SNPs with MMP-2 and MMP-9 serum levels and activity in individuals with CAC. One hundred and fifty-five cases with CAC and 155 healthy individuals as control group from West of Iran were included and frequency of genotypes and alleles of rs243866 and rs3918242 in MMP-2 and MMP-9 genes were determined using PCR-RFLP. We also investigated the serum levels of MMP-2 and MMP-9 and their activity using ELISA and gelatin zymography, respectively. Additionally, serum biochemical parameters including FBS (fasting blood sugar), urea, creatinine, cholesterol, triglyceride, HDL (high-density lipoprotein), LDL (low-density lipoprotein), calcium, and phosphorus as well as blood pressure (systolic blood pressure (SBP) and diastolic blood pressure (DBP)) were measured. Our results showed that both serum levels of MMP-2 and MMP-9 (P < 0.001) and their activity (P < 0.001) were higher in individuals with CAC when compared to the control group. Carrying A and T alleles in MMP-2 -1575G>A (rs243866) and MMP-9 -1562 C>T (rs3918242) SNPs, respectively, may predispose the individuals to CAC by acting as the risk factors. Serum levels and activity of MMP-2 and MMP-9 were found to be higher in CAC cases when compared to the healthy controls. Carriers of A allele in rs243866 SNP and T allele in rs3918242 SNP were shown to have higher MMP-2 and MMP-9 serum levels and activity that may result in increased ECM degradation and support the initiation and development of calcification.

Interaction between Apolipoprotein E and Butyrylcholinesterase Genes on Risk of Alzheimer's Disease in a Prospective Cohort Study

BACKGROUND

An epistatic interaction between the ɛ4 allele of apolipoprotein E (APOEɛ4) gene and the K-variant of butyrylcholinesterase (BCHE-K) genes has been previously reported to increase risk of Alzheimer's disease (AD). However, these observations were largely from case-control studies with small sample sizes.

OBJECTIVE

To examine the interaction between APOEɛ4 and BCHE-K on: 1) the risk of incident AD and 2) rates of change in brain volumes and cognitive performance during the preclinical stages of AD in a prospective cohort study.

METHODS

The study sample for survival analysis included 691 Caucasian participants (age at baseline, 58.4±9.9 years; follow-up time,16.9±9.7 years) from the Baltimore Longitudinal Study of Aging. The neuroimaging sample included 302 participants with 1,388 magnetic resonance imaging (MRI) scans. Cognitive performance was assessed in 703 participants over 4,908 visits.

RESULTS

A total of 122 diagnoses (79 AD, 43 mild cognitive impairment [MCI]) were identified. Participants with both APOEɛ4 and BCHE-K variants had a 3.7-fold greater risk of AD (Hazard ratio [HR] 95% CI=1.99-6.89, p < 0.001) compared to non-carriers of both genes (APOE ɛ4 x BCHE-K interaction p = 0.025). There was no APOE ɛ4-BCHE-K interaction effect on rate of cognitive decline and brain atrophy.

CONCLUSION

The APOE and BCHE genes interact to influence risk of incident AD/MCI but not rates of brain atrophy and decline in cognitive performance before onset of cognitive impairment. This may suggest the epistatic interaction between APOE ɛ4 and BCHE-K on AD risk is disease stage-dependent.

Deleterious Effect of Butyrylcholinesterase K-Variant in Donepezil Treatment of Mild Cognitive Impairment

BACKGROUND

Donepezil is an acetylcholinesterase inhibitor frequently prescribed for the treatment of mild cognitive impairment (MCI) though not approved by the Food and Drug Administration for this indication. In Alzheimer's disease, butyrylcholinesterase (BChE) activity increases with disease progression and may replace acetylcholinesterase function. The most frequent polymorphism of BChE is the K-variant, which is associated with lower acetylcholine-hydrolyzing activity. BChE-K polymorphism has been studied in Alzheimer's disease progression and donepezil therapy, and has led to contradictory results.

OBJECTIVES

To determine whether BChE-K genotype predicts response to donepezil in MCI.

METHODS

We examined the association between BChE-K genotype and changes in cognitive function using the data collected during the ADCS vitamin E/donepezil clinical trial in MCI.

RESULTS

We found significant interactions between BChE-K genotype and the duration of donepezil treatment, with increased changes in MMSE and CDR-SB scores compared to the common allele in MCI subjects treated during the 3-year trial. We found faster MMSE decline and CDR-SB rise in BChE-K homozygous individuals treated with donepezil compared to the untreated. We observed similar interactions between BChE-K genotype and steeper changes in MMSE and CDR-SB scores in APOE4 carriers treated with donepezil compared to controls.

CONCLUSION

BChE-K polymorphisms are associated with deleterious changes in cognitive decline in MCI patients treated with donepezil for 3 years. This indicates that BChE-K genotyping should be performed to help identify subsets of subjects at risk for donepezil therapy, like those carrying APOE4. BChE-K and APOE4 carriers should not be prescribed off-label donepezil therapy for MCI management.

Metformin - a Future Therapy for Neurodegenerative Diseases : Theme: Drug Discovery, Development and Delivery in Alzheimer's Disease Guest Editor: Davide Brambilla

Type 2 diabetes mellitus (T2DM) is a complex, chronic and progressive metabolic disease, which is characterized by relative insulin deficiency, insulin resistance, and high glucose levels in blood. Esteemed published articles and epidemiological data exhibit an increased risk of developing Alzheimer's disease (AD) in diabetic pateints. Metformin is the most frequently used oral anti-diabetic drug, which apart from hypoglycaemic activity, improves serum lipid profiles, positively influences the process of haemostasis, and possesses anti-inflammatory properties. Recently, scientists have put their efforts in establishing metformin's role in the treatment of neurodegenerative diseases, such as AD, amnestic mild cognitive impairment and Parkinson's disease. Results of several clinical studies confirm that long term use of metformin in diabetic patients contributes to better cognitive function, compared to participants using other anti-diabetic drugs. The exact mechanism of metformin's advantageous activity in AD is not fully understood, but scientists claim that activation of AMPK-dependent pathways in human neural stem cells might be responsible for the neuroprotective activity of metformin. Metformin was also found to markedly decease Beta-secretase 1 (BACE1) protein expression and activity in cell culture models and in vivo, thereby reducing BACE1 cleavage products and the production of Aβ (β-amyloid). Furthermore, there is also some evidence that metformin decreases the activity of acetylcholinesterase (AChE), which is responsible for the degradation of acetylcholine (Ach), a neurotransmitter involved in the process of learning and memory. In regard to the beneficial effects of metformin, its anti-inflammatory and anti-oxidative properties cannot be omitted. Numerous in vitro and in vivo studies have confirmed that metformin ameliorates oxidative damage.

The diabetic brain and cognition

The prevalence of both Alzheimer's disease (AD) and vascular dementia (VaD) is increasing with the aging of the population. Studies from the last several years have shown that people with diabetes have an increased risk for dementia and cognitive impairment. Therefore, the authors of this consensus review tried to elaborate on the role of diabetes, especially diabetes type 2 (T2DM) in both AD and VaD. Based on the clinical and experimental work of scientists from 18 countries participating in the International Congress on Vascular Disorders and on literature search using PUBMED, it can be concluded that T2DM is a risk factor for both, AD and VaD, based on a pathology of glucose utilization. This pathology is the consequence of a disturbance of insulin-related mechanisms leading to brain insulin resistance. Although the underlying pathological mechanisms for AD and VaD are different in many aspects, the contribution of T2DM and insulin resistant brain state (IRBS) to cerebrovascular disturbances in both disorders cannot be neglected. Therefore, early diagnosis of metabolic parameters including those relevant for T2DM is required. Moreover, it is possible that therapeutic options utilized today for diabetes treatment may also have an effect on the risk for dementia. T2DM/IRBS contribute to pathological processes in AD and VaD.

Association between butyrylcholinesterase K variant and mild cognitive impairment in the Thai community-dwelling patients

OBJECTIVE

To study the association of the butyrylcholinesterase K variant (BChE-K) and the plasma BChE activity with mild cognitive impairment (MCI) in Thai community-dwelling patients.

METHODS

One hundred patients diagnosed with MCI and 100 control subjects were recruited from the community-dwelling setting in Bangkok, Thailand. The genotype and allele distributions of the BChE-K were determined by polymerase chain reaction and subsequent DNA sequencing. The BChE activity was measured in plasma according to the Ellman's method.

RESULTS

The BChE-K allele frequencies in the Thai community-dwelling patients were in accordance with other ethnics. The BChE-K allele frequency in the control subjects (12%) was higher than that of MCI patients (5.5%), suggesting a protective role of BChE-K for MCI in the Thai community-dwelling patients. The BChE-K homozygotes were significantly associated with lower BChE activity.

CONCLUSION

Our results suggested that the BChE-K may be implicated as a protective factor for MCI in the Thai community-dwelling patients, although a further study with a large sample size is warranted to confirm this.

Association of Butyrylcholinesterase-K Allele and Apolipoprotein E ɛ4 Allele with Cognitive Decline in Dementia with Lewy Bodies and Alzheimer's Disease

BACKGROUND

A common polymorphism of the butyrylcholinesterase gene, the K-variant (BCHE-K) is associated with reduced butyrylcholinesterase (BuChE) activity. Insufficient studies exist regarding the frequency and role of BCHE-K in dementias.

OBJECTIVE

To determine the association of BCHE-K and APOEɛ4 with diagnosis and rate of cognitive decline in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) patients.

METHODS

Genomic DNA from 368 subjects (108 AD, 174 DLB, and 86 controls) from two routine clinical cohort studies in Norway; DemVest and TrønderBrain, were genotyped for BCHE-K and APOEɛ4. The mild dementia DemVest subjects received annual Mini-Mental State Examination assessments for five years.

RESULTS

BCHE-K frequency was lower in DLB (33.9% ; p <  0.01) than in control subjects (51.2%), and was numerically lower in AD as well (38.9% ; p = 0.11). More rapid cognitive decline was associated with the APOEɛ4 genotype, but not with the BCHE-K genotype. In an exploratory analysis of patients who completed all five follow-up visits, there was greater cognitive decline in BCHE-K carriers in the presence of the APOEɛ4 allele than in the absence of these polymorphisms.

CONCLUSION

BCHE-K is associated with a reduced risk for AD and DLB whereas APOEɛ4 is associated with more rapid cognitive decline. The greater cognitive decline in individuals with both APOEɛ4 and BCHE-K alleles require prospective confirmation in well-controlled trials.

Butyrylcholinesterase K variant and Alzheimer's disease risk: a meta-analysis

Background

Although many studies have estimated the association between the butyrylcholinesterase (BCHE) K variant and Alzheimer’s disease (AD) risk, the results are still controversial. We thus conducted this meta-analysis.

Material/Methods

We searched NCBI, Medline, Web of Science, and Embase databases to find all eligible studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association.

Results

We found a significant association between BCHE K variant and AD risk (OR=1.20; 95% CI 1.03–1.39; P=0.02). In the stratified analysis by ethnicity, we observed a significant association between BCHE K variant and AD risk in Asians (OR=1.32; 95% CI 1.02–1.72; P=0.04). However, no significant association between BCHE K variant and AD risk in Caucasians was found (OR=1.14; 95% CI 0.95–1.37; P=0.16). When stratified by the age of AD onset, we found that late-onset AD (LOAD) was significantly associated with BCHE K variant (OR=1.44; 95% CI 1.05–1.97; P=0.02). No significant association between BCHE K variant and early-onset AD (EOAD) risk was observed (OR=1.16; 95% CI 0.89–1.51; P=0.27). Compared with non-APOE ɛ4 and non-BCHE K carriers, no significant association between BCHE K variant and AD risk was found (OR=1.11; 95% CI 0.91–1.35; P=0.30). However, APOE ɛ4 carriers showed increased AD risk in both non-BCHE K carriers (OR=2.81; 95% CI 1.75–4.51; P=0.0001) and BCHE K carriers (OR=3.31; 95% CI 1.82–6.02; P=0.0001).

Conclusions

The results of this meta-analysis indicate that BCHE K variant might be associated with AD risk.

Association of BDNF and BCHE with Alzheimer's disease: Meta-analysis based on 56 genetic case-control studies of 12,563 cases and 12,622 controls

Alzheimer's disease (AD) is a common neurodegenerative disorder that can destroy the memory of sufferers and lead to distress for the individual and society. Brain-derived neurotrophic factor (BDNF) and butyrylcholinesterase (BCHE) are two genes associated with β-amyloid plaques and neurofibrillary tangles that are two key factors in the pathophysiology of AD. The aim of the current meta-analysis was to evaluate the association between BDNF Val66Met (rs6265), BDNF C270T (rs2030324) and BCHE-K (rs1803274) polymorphisms and AD. A comprehensive meta-analysis was performed using the online database PubMed without a time limitation. A total of 56 articles evaluating 12,563 cases and 12,622 controls were selected for the current meta-analysis. The results showed a moderate association of the BDNF C270T polymorphism with the risk of AD in Asians under a dominant model (P=0.03; odds ratio, 1.88; 95% confidence interval, 1.08-3.27). No other significant association was found during the meta-analysis for the other two polymorphisms (P>0.05). The current meta-analysis suggests that BDNF C270T is a risk factor for AD in Asians. This meta-analysis has been, to the best of our knowledge, the most comprehensive meta-analysis of BDNF Val66Met, BDNF C270T and BCHE-K to date.

Butyrylcholinesterase: K variant, plasma activity, molecular forms and rivastigmine treatment in Alzheimer's disease in a Southern Brazilian population

Alzheimer's disease (AD) is a neurodegenerative disorder in which there is a decline of cholinergic function. The symptomatic AD treatment involves the use of ChEIs (cholinesterase inhibitors) as rivastigimine, a dual inhibitor. The human butyrylcholinesterase (BChE) is an enzyme that has specific roles in cholinergic neurotransmission and it has been associated with AD. In the serum, BChE is found in four main molecular forms: G1 (monomer); G1-ALB (monomer linked to albumin); G2 (dimer); and G4 (tetramer). The interaction between the products of BCHE gene and CHE2 locus results in CHE2 C5+ and CHE2 C5- phenotypes. CHE2 C5+ phenotype and BChE-K are factors that influence on BChE activity. This work aimed to verify the proportions of BChE molecular forms, total and relative activity in 139 AD patients and 139 elderly controls, taking into account K variant, CHE2 locus, rivastigmine treatment and clinical dementia rating (CDR) of AD patients. Phenotypic frequencies of CHE2 C5+ and frequency of the carriers of the K allele were similar between groups. Total BChE activity in plasma was significantly lower in AD patients than in elderly controls. Furthermore, we found that reduction on plasma BChE activity is associated directly with AD progression in AD patients and that rivastigmine treatment has a stronger effect on BChE activity within the CDR2 group. The reduction in BChE activity did not occur proportionally in all molecular forms. Multiple regression analysis results confirmed that AD acts as the main factor in plasma BChE activity reduction and that severe stages are related with an even greater reduction. These findings suggest that the reduction of total plasma BChE and relative BChE molecular forms activity in AD patients is probably associated with a feedback mechanism and provides a future perspective of using this enzyme as a possible plasmatic secondary marker for AD.

Epistasis in the risk of human neuropsychiatric disease

Neuropsychiatric disease represents the ideal class of disease to assess the role of epistasis, as more genes are expressed in the brain than in any other tissue. In this chapter, two well-studied neuropsychiatric diseases are examined, Alzheimer's disease (AD) and schizophrenia, which have been shown to have multiple and, often, replicated interactions that associate with clinical endpoints or related phenotypes. In each case, a single gene is represented in a plurality of epistatic interactions, apolipoprotein E (APOE) for AD and catechol-O-methyltransferase for schizophrenia. Interestingly, of the two, only APOE has clear-cut and consistent evidence for a marginal association. Unraveling the underlying reasons is important in understanding both genetic etiology and architecture as well as how to use genetics to provide better personalized treatments.

Distribution of APOE polymorphism in the "Paisa" population from northwest Colombia (Antioquia)

BACKGROUND

The apolipoprotein E (APOE) gene plays a pivotal role in cholesterol metabolism. Since the discovery of the APOE*2 and APOE*4 as the major susceptibility alleles for several diseases including dyslipidemia, atherosclerosis, coronary heart disease, late-onset and early Alzheimer's disease, the APOE genotype might be considered as a potential predictive factor for both epidemiological research and diagnosis.

AIM

The aim of this study is to report on the polymorphism of the APOE gene in the "Paisa" population from northwest Colombia (Antioquia) to obtain a population baseline of the existing variation in this locus.

METHOD

One thousand and one healthy voluntaries were genotyped for the APOE polymorphism using polymerase chain reaction-restriction fragment length polymorphism technique.

RESULTS

The APOE*3/*3 genotype presented the highest frequency (66.33%) and the APOE*4/*4 had the lowest frequency (1.89%). Genotype frequencies comply with Hardy-Weinberg expectations. Allele frequencies obtained for APOE*2, APOE*3 and APOE*4 were 0.075 ± 0.005 (95% CI = 0.063-0.086), 0.814 ± 0.009 (0.797-0.831) and 0.111 ± 0.007 (0.098-0.125), respectively.

CONCLUSION

Although globally the high-to-low APOE frequency follows the E*3 > E*4 > E*2 trend, the present APOE frequency data is in disagreement with some reports from South-American countries.

Angiotensin converting enzyme insertion/deletion (I/D) (rs4646994) and Vegf polymorphism (+405G/C; rs2010963) in type II diabetic patients: Association with the risk of coronary artery disease

HYPOTHESIS

Little is known about the concomitant presence of the angiotensin-converting enzyme (ACE) (rs4646994) D allele and vascular endothelial growth factor(VEGF) (+405G/C; rs2010963) G allele on the susceptibility of coronary artery disease (CAD). Here we examined the hypothesis that ACE-D and VEGF-G alleles act synergistically to increase the severity of CAD in patients with type II diabetes mellitus (T2DM).

MATERIALS AND METHODS

The VEGF (rs2010963) and ACE (rs4646994) genotypes were detected by polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) and PCR, respectively in 510 T2DM patients undergoing their first coronary angiography. Diabetic patients were classified as T2DM patients with and without CAD (control).

RESULTS

The crude odds ratio (OR) for the presence of CAD in ID+DD and D allele carriers were 1.98 (p=0.01) and 1.55 (p=0.001), respectively. Also, adjusted ORs in the presence of normolipidemia and the absence of history of hypertension for the risk of CAD in the either ACE(rs4646994) D allele or VGEF(rs2010963)-G alleles were 2.08 (p=0.004) and 1.75 (p=0.024), respectively. In addition, the concomitant presence of the ACE-D and VEGF-G alleles increased the risk of CAD 2.25-fold (p=0.043).

CONCLUSION

Our results indicated that ACE(rs4646994)-D allele alone and in the presence of VEGF(rs2010963)-G allele can be an important independent risk factor for susceptibility of CAD in T2DM patients even after correcting for conventional risk factors in a population of Iran.

Butyrylcholinesterase genetic variants: association with cocaine dependence and related phenotypes

Objective

The search for genetic vulnerability factors in cocaine dependence has focused on the role that neuroplasticity plays in addiction. However, like many other drugs, the ability of an individual to metabolize cocaine can also influence susceptibility to dependence. Butyrylcholinesterase (BChE) metabolizes cocaine, and genetic variants of the BChE gene (BCHE) alter its catalytic activity. Therefore, we hypothesize that cocaine users with polymorphisms in BCHE can show diverse addictive behaviors due to differences in effective plasma concentrations of cocaine. Those polymorphisms might also influence users to prefer one of the two main preparations (crack or powder cocaine), despite having equal access to both. The present work investigates polymorphisms in BCHE and if those genetic variants constitute risk factors for cocaine dependence and for crack cocaine use.

Methods

A total of 1,436 individuals (698 cocaine-dependent patients and 738 controls) were genotyped for three single nucleotide polymorphisms (SNPs) in BCHE: rs1803274, rs4263329, and rs4680662.

Results

For rs4263329, a nominal difference was found between cases and controls. For rs1803274 (the functional SNP), a statistically significant difference was found between patients who used crack cocaine exclusively and those who used only powder cocaine (P = 0.027; OR = 4.36; 95% CI = 1.18–16.04). Allele frequencies and genotypes related to other markers did not differ between cases and controls or between the two cocaine subgroups.

Conclusions

Our findings suggest that the AA genotype of rs1803274 is a risk factor for crack cocaine use, which is more addictive than powder cocaine use. Further studies are needed in order to confirm this preliminary result and clarify the role of BCHE and its variants in cocaine dependence.

A review of butyrylcholinesterase as a therapeutic target in the treatment of Alzheimer's disease

OBJECTIVE

To examine the role of butyrylcholinesterase (BuChE) in cholinergic signaling and neurologic conditions, such as Alzheimer's disease (AD). The rationale for inhibiting cholinesterases in the management of AD, including clinical evidence supporting use of the dual acetylcholinesterase (AChE) and BuChE inhibitor rivastigmine, is discussed.

DATA SOURCES

PubMed searches were performed using butyrylcholinesterase as a keyword. English-language articles referenced in PubMed as of September 2011 were included. Study Selection and Data Synthesis: English-language articles related to BuChE considered to be of clinical relevance to physicians were included. English-language articles specifically related to AChE were not included, as the role of AChE in cholinergic signaling and the underlying pathology of AD is well documented. Reference lists of included publications were used to supplement the search.

RESULTS

AChE and BuChE play a role in cholinergic signaling; BuChE can hydrolyze acetylcholine and compensate for AChE when levels are depleted. In the AD brain, AChE levels decrease, while BuChE levels are reportedly increased or unchanged, with changes becoming more pronounced during the disease course. Furthermore, BuChE genotype may influence AD risk and rate of disease progression. Strategies that increase acetylcholine levels (eg, cholinesterase inhibitors) demonstrate symptomatic efficacy in AD. Rivastigmine has proven cognitive efficacy in clinical trials, and data suggest that its action is mediated, in part, by inhibition of BuChE. Retrospective analyses of clinical trials provide evidence that BuChE genotype may also influence treatment response.

CONCLUSIONS

AChE-selective inhibitors and a dual AChE and BuChE inhibitor demonstrate symptomatic efficacy in AD. Mounting preclinical and clinical evidence for a role of BuChE in maintaining normal cholinergic function and the pathology of AD provides a rationale for further studies investigating use of rivastigmine in AD and the influence of BuChE genotype on observed efficacy.

Association analysis between K and -116A variants of butyrylcholinesterase and Alzheimer's disease in a Brazilian population

In Alzheimer's disease (AD) a reduction in acetylcholinesterase (AChE) and an increase in butyrylcholinesterase (BChE) activity are observed. K variant (539T) is the most common variant of the BCHE gene and, although controversial, several studies reported association between K variant and AD. Previous results showed that the K variant alone is not capable of diminishing BChE activity, depending on the presence of the -116A variant. Considering that, we conducted a case-control association study using a clinically well defined group of AD patients (n = 82) and age and sex matched control subjects (EC; n = 78) in order to test the association with these variations of BCHE gene in a Brazilian population. The allele, genotype and haplotype frequencies of the K and the -116A variants of BCHE gene were not significantly different between cases and controls. Although not reaching statistical significance, the results suggested that the presence of -116A variant may have a protective effect against AD. The association of the K variant with AD in a controversial manner in different surveys is probably caused by its linkage disequilibrium with -116A that, by reducing BChE activity, potentially increases cholinergic transmission in comparison with usual genotypes.

Butyrylcholinesterase in metabolic syndrome

Butyrylcholinesterase may have a role in a number of metabolic functions and could affect the expression of insulin resistance syndrome. We present our integrated work using clinical, biochemical and bioinformatic approaches to delineate the possible function of this enzyme. Initially, we constructed a phylogenic tree with nucleotides and amino acid sequences and showed the existence of similar sequences in bacteria, plants and in other animals. We also demonstrated a possible pathogenic role for BChE in the common existence of insulin resistance, type 2 diabetes and Alzheimer's disease by in silico method and followed it up with a diabetic mouse study where cognition was slowed along with changes in BChE levels. In the next group of in silico studies, we employed THEMATICS method to identify the amino acids at the active site and later performed docking studies with drugs. THEMATICS predicted two clusters of ionisable amino acid residues that are in proximity: one with two residues and another with 11 showed perturbation in the THEMATICS curves. Using ISIS/Draw 2.5SP4, ARGUSLAB 4.0.1 and HEX 5.1. software. 3-D ligands were docked with BChE motif (from PDB). We did not find any of the ligands studied with significant docking distance, indicating they did not have direct interaction with the active site. Subsequently we performed in silico studies to compare the secondary structure and domain of BChE. Protein-protein interaction showed the following intersections with BChE UBE21, CHAT, APOE, AATF, DF ALDH9A1, PDHX, PONI PSME3 and ATP6VOA2. The integrative physiological roles of proteins with poorly known functions can be approached by generating leads in silico, which can be studied in vivo, setting into movement an iterative process.

Differential levels of apolipoprotein E and butyrylcholinesterase show strong association with pathological signs of Alzheimer's disease in the brain in vivo

Recently, we reported that 3 of the known risk factors of Alzheimer's disease (AD), i.e., advanced age, apolipoprotein E (ApoE) ε4, and female gender, are associated with differential levels of ApoE proteins and butyrylcholinesterase (BuChE) in the cerebrospinal fluid (CSF) of AD patients. The ApoE ε4 allele and certain BuChE polymorphisms synergistically affect the conversion rate of mild cognitive impairment (MCI) to AD. Here, we investigated interrelationships between ApoE and BuChE levels, and pathological markers of AD in vivo. CSF from patients with probable AD, assessed for cerebral glucose metabolism (CMRglc; n = 50) and Pittsburgh compound B (PIB) retention (β-amyloid [Aβ] load, n = 29) by positron emission tomography (PET), was used for measurement of BuChE, ApoE, Aβ, tau, phosphorylated tau (P-tau) and interleukin-1β (IL-1β) levels. Levels of ApoE and BuChE strongly correlated with CMRglc (fluorodeoxyglucose [FDG]-PET, r = 0.54, p < 0.0001, n = 50), cerebral Aβ load (PIB retention, r = 0.73, p < 0.0001, n = 29), and CSF P-tau (r = 0.73, p < 0.0001, n = 33). High ApoE protein was tied to low CMRglc and high PIB retention and P-tau. BuChE levels had opposite relationships. Other CSF covariates were levels of interleukin-1β and Aβ(42) peptide. The pattern of the patients' cognitive Z-scores strongly supported these observations. High ApoE protein was also linked to changes in 3 of the biodynamic properties of BuChE. In vitro analysis indicated that high ApoE protein levels were related to an increased pool of dormant BuChE molecules with an abnormally high intrinsic catalytic rate in CSF, which was "turned on" by excess Aβ peptides. The findings suggest that abnormally high levels of ApoE may play a causative role in the pathological events of AD, particularly those involving the early cholinergic deficit in the AD brain, through modulation of cholinesterases activities, hence disturbing the acetylcholine-dependent activity of neurons and nonexcitable cells such as glial cells.

BuChE K variant is decreased in Alzheimer's disease not in fronto-temporal dementia

Alzheimer's disease (AD) is characterized by a significant reduction in AcetylCholinesterase and an increase in ButyrylCholinesterase (BuChE) activity. The existence of polymorphic regions on the BuChE gene has been previously described; the most frequently found polymorphism is the so-called K variant, which leads to a 30% decreased enzymatic activity. Different studies reported a positive association between K variant and AD, strongest among late-onset AD and Apolipoprotein E (APOE) e4 carriers. We analyzed APOE and BuChE polymorphisms in 167 AD and 59 fronto-temporal dementia (FTD) patients compared with 129 healthy controls (HC). We reported a significantly lower frequency of the BuChE K variant in AD compared with HC and FTD and a significant increased frequency of the K variant in FTD. These results are in agreement with the known increase of the BuChE activity in AD and support the evidence of different molecular pathways involved in the pathogenesis of AD and FTD.

The apolipoprotein E ε4 allele plays pathological roles in AD through high protein expression and interaction with butyrylcholinesterase

The apolipoprotein E (ApoE) ε4 allele has consistently been established as an Alzheimer's disease (AD) risk factor, but its pathological contribution to AD is obscure. Certain butyrylcholinesterase (BuChE) polymorphisms together with the ApoE ε4 allele synergistically increase the risk of AD. In addition, AD risk factors, i.e. advanced age, female gender and ApoE ε4 are associated with different levels of CSF BuChE in AD patients, and BuChE protein attenuates Aβ fibrillization in vitro. Here we investigated the roles of ApoE and BuChE gene products as modulators of pathological features of AD in vivo. We found that AD risk factors were associated with different levels of ApoE protein in the CSF of AD patients (n=115). Women and ApoE ε4 carriers had the highest levels of ApoE protein (up by 50-120%, p<0.01-0.0001), which were increased with age (r=0.30, p<0.0006). The CSF surrogate markers of pathological features of AD, i.e. high tau and P-tau, low Aβ(42) and high tau/Aβ(42) ratio, were associated with high levels of ApoE protein. Intriguingly, high ApoE protein levels were not only associated with low amounts of BuChE, but they also altered the aging and activity of this enzyme in concentration- and isoform-dependent manners, particularly in the presence of Aβ peptides. Both ApoE and BuChE levels were also differentially related to levels of the proinflammatory cytokine IL-1β. In conclusion, ApoE ε4 might impart its pathological role through high protein expression and interaction with BuChE, which in turn might modulate central cholinergic activity and Aβ load in the brain.

Butyrylcholinesterase K variant and the APOE-epsilon 4 allele work in synergy to increase the risk of coronary artery disease especially in diabetic patients

We have previously shown that butyrylcholinesterase-K (BCHE-K, G1615A/Ala539Thr) variant increases the risk of coronary artery disease (CAD). In addition, we have found that the presence of APOE-epsilon 4 allele augments the risk of CAD in patients with type II diabetes mellitus (T2DM/CAD). Here we explored the concomitant presences of two alleles of the BCHE-K and APOE-epsilon 4 in increasing the risk of CAD or diabetes in T2DM patients with or without CAD and CAD patients without T2DM. This case-control study comprised 631 subjects undergoing their first coronary angiography. They were matched and randomly assigned into four groups: type II diabetic patients with no sign of CAD (T2DM), type II diabetic patients with CAD/ND (T2DM/CAD), CAD patients with no sign of diabetes (CAD/ND), and healthy individuals (NCAD/ND). BCHE-K variant and APOE genotypes were detected by PCR-RFLP and serum lipid level was measured enzymatically. We found that BCHE-K and APOE-epsilon 4 allele act synergistically to increase the risk of CAD in both T2DM, non-diabetic and total CAD (TCAD = T2DM/CAD + CAD/ND) individuals. The level of synergy 1.5 and 1.2 fold are higher in CAD patients (OR = 4.5; P = 0.011) with T2DM than the non-diabetic CAD patients (OR = 3.07; P = 0.024) and TCAD patients (OR = 3.74; P = 0.018), respectively. The CAD subjects with and without T2DM and TCAD patients carrying both APOE-epsilon 4 allele and BCHE-K had significantly lower plasma HDL-C (P values = 0.008, 0.047, and 0.036, respectively) and higher plasma LDL-C (P values = 0.025, 0.048, and 0.04, respectively), than that of the control carriers both APOE-epsilon 4 and BCHE-K. We have found that BCHE-K and APOE-epsilon 4 allele not only act synergistically to increase the risk of CAD, particularly in T2DM subjects in population from western Iran, who have high levels of LDL-C and low levels of HDL-C, suggesting that a specific therapeutic intervention should be considered for these particular groups of patients.

Emerging hypotheses regarding the influences of butyrylcholinesterase-K variant, APOE epsilon 4, and hyperhomocysteinemia in neurodegenerative dementias

Non-enzymatic functions of butyrylcholinesterase (BuChE) include prevention of the aggregation of amyloid-beta peptide (A beta) in a concentration-dependent manner. This is mediated by the C-terminus of the protein, distal from the enzymatic site. The BuChE-K variant polymorphism lowers expression of BuChE protein and/or alters C-terminal activity. In combination with factors that increase production or reduce elimination of A beta, and/or increase susceptibility to A beta toxicity - such as the apolipoprotein E (APOE) epsilon 4 allele and/or hyperhomocysteinemia - BuChE-K may accelerate cholinergic synaptic and neuronal damage and cognitive decline. A beta-mediated damage to ascending cholinergic pathways may be further accentuated by Lewy body and/or cerebrovascular disease. As the disease advances and functioning cholinergic synapses disappear, both the rapid cognitive decline and response to cholinesterase inhibitor therapy in individuals with these factors may diminish. Non-enzymatic functions of the BuChE protein, APOE epsilon 4 status and hyperhomocysteinemia influence the progression of pathology, symptom expression, and response to cholinesterase inhibition in a stage-specific manner in neurodegenerative disorders associated with Alzheimer, Lewy body and vascular pathology.

Serum butyrylcholinesterase activity and phenotype associations with lipid profile in stroke patients

BACKGROUND

Butyrylcholinesterase (BuChE) catalyzes the hydrolysis of acetylcholine and other choline esters and is also involved in lipid metabolism. The purpose of this study was to investigate any association between BuChE serum phenotype and activity and lipid profile of ischemic stroke patients.

METHODS

We determined serum BuChE activities and phenotypes, and levels of total cholesterol (TC), LDL-C, HDL-C and triacylglyerol (TG) in 33 patients with acute ischemic stroke within 12 h of the onset of the attack and 29 controls.

RESULTS

The mean (+/-SD) serum BuChE activity and the BuChE of U/A phenotype in the stroke individuals were significantly lower and higher than that of the control (315 (+/-124) IU/L. vs. 384 (+/-99) IU/L, p=0.02, t=-2.4 and 21.2% vs.3.4%, p=0.026 respectively).

CONCLUSIONS

Our results showed that a negative correlation between BuChE activity with TC level, in addition the frequency of BuChE phenotypes with low activity is high in stroke patients, who have high levels of cholesterol, may have increased susceptibility to stroke.

Synergistic effect of apolipoprotein E epsilon4 and butyrylcholinesterase K-variant on progression from mild cognitive impairment to Alzheimer's disease

OBJECTIVE

To evaluate the synergistic effects of the apolipoprotein E (APOE) epsilon4 and butyrylcholinesterase K-variant (BCHE-K) alleles on progression to Alzheimer's disease (AD) in individuals with mild cognitive impairment (MCI).

METHODS

This was a post-hoc exploratory analysis from a 3-4-year, randomized, placebo-controlled study of rivastigmine in participants with MCI (InDDEx study). Participants who consented to genetic testing were included in the current analyses. The incidence of progression to AD, cognitive decline and changes in MRI brain volumes were investigated in participants from the placebo arm of the InDDEx study.

RESULTS

Of the 1018 participants in the overall study, 464 were successfully genotyped for both APOE and butyrylcholinesterase. Of these, 68 (14.7%) carried > or =1 APOE epsilon4 and > or =1 BCHE-K allele. The presence of APOE epsilon4 was associated with a significantly higher incidence of progression to AD whereas the presence of BCHE-K had no independent effect on progression. A synergistic effect of the combined presence of APOE epsilon4 and BCHE-K on the time to clinical diagnosis of AD and on MRI brain volumes was seen. Progression to AD and hippocampal volumetric loss was greatest in participants who carried both APOE epsilon4 and BCHE-K alleles and lowest in BCHE-K carriers without the APOE epsilon4 allele.

CONCLUSION

In MCI, the risk of cognitive decline, hippocampal volumetric loss and progression to AD seems to be the greatest in individuals who carry at least one copy of both the BCHE-K and APOE epsilon4 alleles.

Butyrylcholinesterase K variants increase the risk of coronary artery disease in the population of western Iran

The conflicting results of several studies suggest that there is an association between the butyrylcholinesterase-K variant (BCHE-K, G1615A/Ala539Thr) and the risk of developing coronary artery disease (CAD) in diabetes and non-diabetic subjects. The objective of this study was to determine whether the presence of the BCHE-K variant exacerbates the risk of CAD in patients from western Iran with and without type 2 diabetes mellitus (T2DM). This case-control study comprised 464 subjects undergoing their first coronary angiography. They were matched and randomly assigned into four groups: CAD+T2DM+ (CAD/T2DM), CAD+DM(-) (CAD/ND), CAD(-)DM+ (T2DM/NCAD) and CAD(-)DM(-)(control). The BCHE-K variant was detected by PCR-RFLP. The BCHE-K allele frequency in CAD patients with and without T2DM [total CAD (TCAD)] and separately for each group (CAD/T2DM and CAD/ND) was significantly higher than in the control group (21.1 % versus 13.3 % (p = 0.001), 22.4 % versus 13.3 % (p = 0.001) and 19.7 % versus 13.3 % (p = 0.015), respectively). The odds ratios (ORs) for the BCHE-K heterozygous and homozygous variants in TCAD subjects were 1.65 (95 % CI 1.17-2.3; p = 0.004) and 4.3 (1.05-19.4; p = 0.048); for CAD/T2DM individuals 1.76 (1.2-2.6; p = 0.004) and 4.73 (0.96-23.3; p = 0.052); and for CAD/ND patients 1.53 (1.05-2.3; p = 0.029) and 3.88 (0.8-19.7; p = 0.7), respectively. The OR of the BCHE-K allele was found to be 1.74 (1.1-2.4; p = 0.001) in TCAD subjects, 1.87 (1.12-1.48; p = 0.001) in the CAD/T2DM group and 1.59 (1.04-1.4; p = 0.016) in CAD/ND subjects. These data suggest that the BCHE-K allele increases the risk of CAD in the population (with and without DM) in western parts of Iran, and its presence intensifies the risk of CAD in T2DM. The fact that the BCHE-K allele, even in the heterozygous form, exacerbates the risk of CAD in this population, suggests that a specific therapeutic intervention should be considered for this particular group of patients.

Butyrylcholinesterase, ApoE and Alzheimer's disease in a population from the Canary Islands (Spain)

AIM

Cholinergic dysfunction is a major neurochemical feature in Alzheimer's disease (AD), accountable for many cognitive dysfunctions and some psychiatric symptoms. Butyrylcholinesterase (BChE) is one of the cholinesterases with increased activity in the brain of Alzheimer's patients. Several mutations code for different BChE, such as the K variant, which is the most common and is capable of reducing BChE activity by 30%. We studied the relationship between this K variant and Alzheimer's disease in our population from the Canary Islands (Spain).

PATIENTS AND METHODS

We used DNA PCR-RFLP techniques to compare 282 patients who had been diagnosed with probable Alzheimer's disease--according to NINCS-ADRDA criteria--with 312 control subjects confirmed to be free of cognitive impairment as assessed by using the CAMDEX cognitive subscale CAMCOG.

RESULTS

In our population the K variant of BChE is linked to the age of diagnosis of Alzheimer's disease, since AD individuals with this allele presented the disease at a later stage. No other susceptibility relations are exposed in this study. In addition, the BChE allelic frequencies in our population are higher than those previously reported.

Determination of butyrylcholinesterase (BChE) phenotypes to predict the risk of prolonged apnea in persons receiving succinylcholine in the healthy population of western Iran

OBJECTIVE

The best known clinical application of serum BChE assay is to predict abnormally prolonged apnea following the application of the muscle relaxant succinylcholine. The aim of the present study was to assess the frequency of BChE phenotypes and to predict the risk of apnea for those receiving succinylcholine among the residents in western Iran.

METHODS

We examined the frequency of nine BChE phenotypes in 1548 volunteers including 816 males and 732 females with the mean age of 35+/-15 years from an apparently healthy group living in western Iran. The frequencies of BChE phenotypes were determined using BChE activity measurements and by inhibition with dibucaine, fluoride, and the compound Ro2-0683 (Hoffman-La-Roche).

RESULTS

The reference range for serum total BChE activity was 4600-14000 U/L (using butyrylthiocholine iodide as substrate). The mean value obtained for men (9030 U/L) was significantly (p<0.05) higher than that for women (8550 U/L). The frequencies of four alleles U, A, F, S were calculated to be 0.9826, 0.0165, 0.008 and 0.001, respectively. The frequency of phenotypes of BChE was as follows: normal phenotype (UU) 95.5%, moderate sensitive to succinylcholine including UA,US,UF phenotypes was 3.9% and hypersensitive to succinylcholine (AA, AF, AS, FF, SS) was 0.58%.

CONCLUSION

This study indicates that the population of western Iran has a medium frequency of succinylcholine-sensitive individuals compared to other populations. We suggest that determination of BChE activity and phenotype by the micro automated method is well suited to pre-operative screening and detection of at-risk of prolonged apnea in persons receiving succinylcholine in the healthy population of western Iran.

Molecular basis of succinylcholine sensitivity in a prairie Hutterite kindred and genetic characterization of the region containing the BCHE gene

The tetrameric glycoprotein butyrylcholinesterase (BChE; EC 3.1.1.8) is one of two enzymes that hydrolyze choline esters. The controlling gene (BCHE) is comprised of four coding exons and is located on chromosome 3q26. Based on BChE activity measurements in the presence and absence of dibucaine, usual (designated U) and atypical (designated A) gene products have been distinguished. Homozygotes for the A gene product are at risk for prolonged apnea following exposure to the surgical anesthetics succinylcholine or mivacurium. In this report, we detail biochemical and molecular investigations of succinylcholine sensitivity in a prairie Hutterite kindred. Our results establish that BChE activities in the family members are impacted by two distinct BCHE mutations, namely, c.209A>G p. D70G and c.1615G>A p. A539T. However, homozygotes for the c.209A>G mutation (i.e., atypical or A) are the only individuals whose BChE activity could lead to adverse reactions to succinylcholine. Interestingly, haplotype analysis of the chromosomal region containing BCHE indicates that the c.209A>G mutation is carried on a unique haplotype, suggesting that it was likely introduced into the population only once. Conversely, the c.1615G>A mutation is carried on various haplotypes and was likely introduced into the population more than once.

Alzheimer's disease and type 2 diabetes mellitus: the cholinesterase connection?

Alzheimer's disease and type 2 diabetes mellitus tend to occur together. We sought to identify protein(s) common to both conditions that could suggest a possible unifying pathogenic role. Using human neuronal butyrylcholinesterase (AAH08396.1) as the reference protein we used BLAST Tool for protein to protein comparison in humans. We found three groups of sequences among a series of 12, with an E-value between 0–12, common to both Alzheimer's disease and diabetes: butyrylcholinesterase precursor K allele (NP_000046.1), acetylcholinesterase isoform E4-E6 precursor (NP_000656.1), and apoptosis-related acetylcholinesterase (1B41|A). Butyrylcholinesterase and acetylcholinesterase related proteins were found common to both Alzheimer's disease and diabetes; they may play an etiological role via influencing insulin resistance and lipid metabolism.

Peripheral cholinergic disturbances in Alzheimer's disease

The most pronounced neurochemical abnormality in Alzheimer's disease (AD) is cholinergic dysfunction in the central nervous system. Peripheral tissues may also be affected, however, including blood. The present study undertook to determine the activity of acetylcholinesterase (AChE) and its molecular forms in erythrocytes, lymphocytes and platelets of normal elderly subjects and probable AD cases. These samples contained dimeric globular (G2), tetrameric globular (G4) and asymmetric (A12) AChE forms, but no globular monomeric (G1) enzyme. In both lymphocytes and platelets, the major AChE molecular form was G2 (approximately 80%), with G4 and A12 forms accounting for nearly equal portions of the remainder. Total AChE activities and measured sedimentation coefficients were similar in the control and AD samples (from patients with mild and moderately severe cognitive deficiency). However, the groups differed significantly in the proportion of certain AChE molecular forms. Thus, as compared with controls, the amount of A12 AChE in the AD samples was increased 148 and 161% in lymphocytes and platelets, respectively. Genotyping for apolipoprotein E (ApoE) and the butyrylcholinesterase K (BCHE-K) variant, carried out using the polymerase chain reaction, showed that AD patients carried the ApoE4 allele at a significantly higher frequency than the controls. On the other hand there were no significant group differences in the occurrence of the BCHE-K variant and no synergism between ApoE alleles and the BCHE-K variant in our Hungarian AD population.